The Metropolitan Police will deploy 650 officers to busy London junctions at rush hour in response to the recent wave of cycling deaths.
The surge will see 2,500 officers hand out leaflets and fixed penalty notices at 166 junctions marked as the capital's worst.
It comes after six cyclists died in two weeks in collisions with lorries, buses, and coaches - some mere hours apart.
Superintendent Rob Revill of the Safer Transport Command said: "Every road death is a needless tragedy that wreaks devastation on the victim's friends and family. Every serious injury is life-changing and distressing.
"This operation will be intensive and far-reaching. Our aim is to reduce the appalling number of people who die or are injured on London's roads each year.
"Traffic and Safer Transport officers will be out in force, and even officers who don't specialise in traffic policing will be watching and dealing accordingly with anyone they see breaking the law."
On Wednesday, London Mayor Boris Johnson defended his record by saying cyclist deaths had fallen from 102 between 2001 and 2007 to 81 between 2008 and 2013. But Green rival Baroness Jones said the rate of cyclists killed or injured had risen since 2008.
Meanwhile the House of Commons Transport Committee announced it would hold an oral evidence session on December 2 to examine drivers' behaviour and ask whether new "cycling superhighways" are safe.
One victim, 24-year-old Russian tech entrepreneur Verena Minakhmetova, was killed on the deadly Bow roundabout where two people died in winter 2011.
Committee chairman Louise Ellman said: "Many of these casualties involve large vehicles, especially HGVs, and there is now debate about whether they should be banned from city centres at peak times."